How can I become less boring and stiff?

I'm shy and I feel it gets worse, the older I get. It doesn't help, that I live in a country, where I'm not a native and where I have to speak english, which is not my first language. I want to be charming, funny and compionate, but I feel stiff, boring and (I'm half german) like a military person. People here are very easygoing and relaxed, and I believe I'm too, somewhere deep inside, but on the outside I feel tense when I'm with a group and even worse when I think about going out and flirting with a man. How can I change the way I interact with people? I am interested in other people and I would like to show that, but I feel my questions sound more like an interrogation than a friendly chat. And I also would like to feel more relaxed and less tense.